The use of stents to maintain the patency of bodily lumens is well known. are typically delivered via a catheter in an unexpanded configuration to a desired bodily location. Once at the desired bodily location, the stent is expanded and implanted in the bodily lumen. The stent may self-expand or may be mechanically expanded. Where a self-expanding stent is used, the stent is typically retained on the catheter via a retention device such as a sheath. The stent may be deployed by retracting the sheath from over the stent. Where a mechanically expandable stent used, a radially outward force is typically applied to the stent to expand it. The may be applied via an expandable member such as a balloon or via any other mechanical device.
Stents are used in an array of bodily vessels including the coronary arteries, the peripheral arteries, arteries of the neck, cerebral arteries, veins, biliary ducts, urethras, ureters, fallopian tubes, bronchial tubes, the trachea, the esophagus and the prostate.
Currently available stents include tubular stents such as the NIR(trademark) stent as well as coil stents. Tubular stents are typically formed from tubes or from sheets of material from which material has been removed to form openings.
Coil stents typically are formed of a wire or strand which has been wound into coil shape. Coil stents can exhibit a high degree of flexibility, including bendability and longitudinal flexibility which facilitates delivery of the stent through tortuous bodily vessels. Accurate sizing of coil stents, however, can be quite challenging.
There remains a need for coil stents which are flexible and which can be easily and accurately sized to the vessels in which they are implanted.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not to be used for interpreting the scope of the claims.
In one embodiment, the invention is directed to an implantable coil stent comprising a first curved segment and a second curved segment and an link extending between the first and second curved segments. The first and second curved segments arc about the longitudinal axis of the stent. Desirably, the expandable link has at least one bend therein.
Where the stent comprises a plurality of expandable links including a first expandable link and a second expandable link, desirably the second expandable is spaced along the stent from the first expandable link by at least 90 degrees and more desirably, by at least 180 degrees.
Desirably, the expandable segment is made of a first material and the curved segment of a second material. The first material may be stainless steel and the second material may be nitinol. Other combinations are also within the scope of invention. Optionally, the curved segments are in the form of one or more wires having an outer layer of material and a radiopaque core.
The invention is also directed to a coil stent comprising a first segment which curves about the longitudinal axis of the stent, a third segment which curves about the longitudinal axis of the stent and a second segment disposed between the first and third segments where the first and third segments are formed of a first and the second segment is formed of a second material different from the first material. The first, second and third segments are joined end-to-end. Desirably, second segment has at least one bend therein. The second segment may have a plurality of bends therein.
The first material desirably is a shape memory material and the second desirably is stainless steel. The first material may be adhesively joined to the material or joined via any other suitable technique.
The invention is further directed to a medical coil implant for implantation in a bodily vessel. The implant comprises a strand having a plurality of winding which wind about the longitudinal axis of the implant and a plurality of linking segments, the linking segments extending between winding segments which are adjacent one another along the coil. Each linking segment has at least one bend. Desirably, the linking segments are made of a first material and the winding segments are made of a second material different from the first material. Winding segments which are adjacent to linking segments may be adhesively bonded soldered thereto or joined by any other suitable techniques.
It is also within the scope of the invention for the linking segments and the winding segments to be made from the same material, the linking segments been subjected to a different treatment than the winding segments. The linking segments and the winding segments may optionally be made of a shape memory material, for example nitinol. The shape memory material in the linking segments may be subjected to a different heat treatment or annealing than the shape material in the winding segments. The medical coil implant may be provided in the form of a stent, vena cava filter or vaso-occlusive device.
The invention is also directed to any of the inventive medical devices disclosed herein in combination with a medical balloon, where the medical device is disposed about the medical balloon.
The invention is further directed to methods of deploying any of the inventive medical devices disclosed herein at a desired bodily location. In accordance with embodiment of the invention, a medical device delivery catheter comprising any of the inventive medical devices disclosed herein is provided. The catheter is in a bodily vessel to a desired location in the body and the inventive medical device caused to expand to a first size. The expandable links are then expanded to expand the medical device to a second size. The expansion of the expandable links may be accomplished by inflating a medical balloon or expanding any other mechanical expansion device disposed within the inventive medical device or via other suitable method.
Additional details and/or embodiments of the invention are discussed below.